92L still a threat to develop; Igor a hurricane; TD 12 forming near Africa

By: Dr. Jeff Masters , 2:18 PM GMT on September 12, 2010

Share this Blog
1
+

Tropical disturbance (92L) over the Central Caribbean, a few hundred miles south of the Dominican Republic, remains a threat to develop into a tropical depression. Satellite loops this morning show 92L may be starting to form a surface circulation, and an Air Force Hurricane Hunter aircraft will investigate 92L this afternoon to see if a tropical depression is forming.

The storm has only a modest area of heavy thunderstorm with limited low-level spiral banding and upper-level outflow, thanks to an infusion of dry air last night that disrupted the storm. Long range radar out of Puerto Rico shows that heavy rains are affecting that island, but there is no rotation to the radar echoes evident. Wind shear over 92L is low, 5 - 10 knots. The waters beneath are hot, 29.5°C, and these warm waters extend to great depth. Water vapor satellite loops show a large area of dry air lies to the north and west of 92L, and this dry air could interfere with development at times over the next few days.


Figure 1. Morning satellite image of 92L.

Track forecast for 92L
The disturbance is moving west to west-northwest at 15 mph, and steering currents favor a continuation of this motion for the next three days. Model support for development is scattered. The GFS and NOGAPS models do not develop 92L. The GFDL and ECMWF models predict development, with a track taking 92L into Belize or Mexico's Yucatan Peninsula on Wednesday. On this track, the southern Dominican Republic can expect heavy rains of 3 - 6 inches today through Monday morning; southern Haiti can expect similar rains tonight through Monday night, and Jamaica and the Cayman Islands can expect heavier rains of 4 - 8 inches Monday and Tuesday. Eastern Cuba can expect rains in the 2 - 4 inch range. Once 92L crosses the Yucatan, the ridge of high pressure steering it is expected to remain in place, forcing 92L to a second landfall in Mexico south of the Texas border.

Intensity forecast for 92L
NHC is putting the odds of 92L developing into a tropical depression by Tuesday at 50%; I'd put them higher, at 70%. However, time is running out for 92L to become a hurricane before hitting the Yucatan Peninsula on Wednesday. Given the current disorganized state of 92L, it would be difficult for it to intensify quickly enough to become a hurricane by then. The storm may also suffer another of its mysterious evening collapses, where it loses most of its heavy thunderstorm activity. However, the SHIPS model predicts wind shear will remain low, 5 - 10 knots, through the period, and water temperatures are certainly warm enough to support development. The main detriment to intensification is likely to be dry air, and 92L could wrap in some of the dry air to its northwest at times, slowing down development. There are a number of research flights being made into 92L this afternoon that should help long-term efforts to make better predictions in the future on whether or not disturbances like this will develop or not.


Figure 2. Morning satellite image of Igor.

Igor
Hurricane Igor appears destined to become a large and powerful major hurricane over the Central Atlantic in the days to come. Wind shear is low, 5 - 10 knots, and is expected to drop below 5 knots for the next five days. Waters are warm, 28°C, and will warm to 29°C by Wednesday. Igor has moistened its environment enough to keep the dry air of the Saharan Air Layer (SAL) at bay. Igor is undergoing a period of rapid intensification today, and will probably be a Category 3 or 4 hurricane by Monday.

The track forecast for Igor remains unchanged. Igor will move west under the influence of a strong ridge of high pressure for the next 2 - 3 days, then turn more to the west-northwest then northwest in response to the steering influence of a broad trough of low pressure moving across the Western Atlantic on Tuesday and Wednesday. This should allow Igor to pass several hundred miles to the northeast of the Lesser Antilles. In the longer range, Igor may be a threat to Bermuda, and does have a small chance of making landfall on the U.S. East Coast or Canada. Climatology shows that about 15% of all tropical cyclones that have existed at Igor's current position have gone on to hit the U.S. East Coast; these odds are about 10% for Bermuda and 10% for Canada. The forecast steering pattern for the period 5 - 12 days from now from the ECMWF and GFS models shows a continuation of the pattern we've seen all hurricane season, with regular strong troughs of low pressure moving off the U.S. East Coast. This pattern favors Igor eventually recurving out to sea without affecting any land areas. Recent runs of the ECMWF model indicate that these troughs may not be as intense as previously thought, so it is possible Igor has a higher chance than usual to hit land than climatology suggests. One wild card may be the possible development of TD 12 behind Igor. If TD 12 develops into a hurricane, and moves close to Igor, as some of the models are suggesting, the two hurricanes could rotate around a common center, forcing Igor more towards the coast of the U.S. The long term fate of Igor is difficult to predict at this point.

Tropical Depression Twelve forms
Tropical Depression Twelve formed between the Cape Verdes Islands and coast of Africa this morning, and is already affecting the Cape Verdes with winds near tropical storm strength; sustained winds of 35 mph were recorded in the northwest Cape Verdes this morning. You can follow the progress of TD 12 through the Cape Verdes today using our wundermap.

Next post
I'll have a new post Monday morning, and perhaps late this afternoon if events warrant.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 3796 - 3746

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85Blog Index

3796. scott39
Goodmorning, Igor is a sight to behold.
Member Since: Posts: Comments:
3794. stormy3
Quoting StormW:
Just dropping in to say good morning before analysis and gettin' kids off to school.
Morning StormW, hope you have a good report for where all this activity is going?
Member Since: Posts: Comments:
Quoting KerryInNOLA:

CONUS looks safe now, but trough could split.


Bermuda is in the center of that cone. That island dodges so many bullets that I can't believe it. I bet this one will miss too.
Member Since: Posts: Comments:
Quoting StormW:
Just dropping in to say good morning before analysis and gettin' kids off to school.


Morning Mr. Storm!!
Member Since: Posts: Comments:
Good morning Igor.
Member Since: Posts: Comments:
Computers sure makes it seem like Bermuda is going to be in trouble.
Member Since: Posts: Comments:
if Igor continues to move west, the NHC will have no choice but to adjust the track to the south, just like Earl. I don't see Igor turning WNW till around 53-55W
Member Since: Posts: Comments:
Coming off of Africa tomorrow is yet another prime candidate:

CLICK FOR LARGER IMAGE

Tropical weather-related image
Member Since: Posts: Comments:
how do you post a jpeg pic, can someone tell me?? Thanks
Member Since: Posts: Comments:
Good morning all.. relatively new to all of this. Igor looks like something out of a science book. When is he gonna make the turn?
Member Since: Posts: Comments:
Quoting traumaboyy:


I'll drink to that!!



Anybody got working radar off Jamaica? The only links I find show nothing when clicking play.

Member Since: Posts: Comments:
3783. msphar
Lift baby lift. Going West is getting so old. Time for a change.
Member Since: Posts: Comments:
What a beast Igor is. Can't wait to see him in Vis.
Member Since: Posts: Comments:
Quoting stormy3:
traumaboy, you look familiar. also nurse (RN). where you located? I'm from Tampa area. closely monitoring all storm potential as part of emergency assist for at home patients. On leave due to health.


west of Tallahassee about 50 miles
Good morning fellow nurse
Member Since: Posts: Comments:
3780. stormy3
traumaboy, you look familiar. also nurse (RN). where you located? I'm from Tampa area. closely monitoring all storm potential as part of emergency assist for at home patients. On leave due to health.
Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
Quoting negriltracy:


Yup but this one has been so erratic over the last few days it's hard to tell what it will do next!!!


I'll drink to that!!
Member Since: Posts: Comments:
Quoting traumaboyy:


No new theories...been erratic all night.....but sure is blowing up in your neck of the woods....going to be a wet day but you already knew that!!


Yup but this one has been so erratic over the last few days it's hard to tell what it will do next!!!
Member Since: Posts: Comments:
Quoting negriltracy:
Lots of thunder and lightning now with wind picking up a bit...does anyone have any new theories on 92?
Thanks!!!


No new theories...been erratic all night.....but sure is blowing up in your neck of the woods....going to be a wet day but you already knew that!!
Member Since: Posts: Comments:
Lots of thunder and lightning now with wind picking up a bit...does anyone have any new theories on 92?
Thanks!!!
Member Since: Posts: Comments:
Quoting KerryInNOLA:
Coming down for a convention or fun or both? Anyway I'll send your regards to the E Man.


FUN!!!
Member Since: Posts: Comments:
3773. msphar
Igor, time for some heavy lifting
Member Since: Posts: Comments:
Quoting KerryInNOLA:
Elway is recovering from pancreatitis. His Doctor says his tavern days are over, but Elway says as soon as he gets out he's going to buy everybody a round. Poor boy has no sense.


We be there second weekend november....I buy Elway a drink!!
Member Since: Posts: Comments:
Quoting btwntx08:
convection is poping around with 92L


you said that 24 hours ago!!
Member Since: Posts: Comments:
Quoting KerryInNOLA:

Igor not annular anymore. EWRC soon. Then Igor will become gigantic in size. Nothing to stop it. Hope it misses. God help us.


Amen Kerry....Bro still at the tavern??
Member Since: Posts: Comments:
Quoting negriltracy:
Rain starting to come down in Kingston Jamaica now but not much wind yet, hope it stays this way :)


Yes...maybe just a little rain!!
Member Since: Posts: Comments:
Quoting btwntx08:
woah finally some low level convergence finally


Bout time!!
Member Since: Posts: Comments:
This thing looks like a CAT 5, but I bet they won't designate it without aircraft inspection.

Click photo for [animation file ....]


[Link]
Member Since: Posts: Comments:
hey guys 92L COC seems to be around 16.2N 75.5W
Member Since: Posts: Comments:
convection still has time to build has untill D-max ends and then we could have some slight RI when it does develops
Member Since: Posts: Comments:
Based on the latest models and tracking maps, I would not feel at all comfortable to be on Bermuda next weekend.
Member Since: Posts: Comments:
To wile away the time until the next NHC.Advisory on H.Igor
Invest92L
09Sep . 12pmGMT - - 12.0n57.6w - - 20knots - - 1009mb - - NHC-ATCF
09Sep . 06pmGMT - - 12.2n58.3w - - 20knots - - 1009mb - - NHC-ATCF
10Sep . 12amGMT - - 12.4n59.0w - - 20knots - - 1009mb - - NHC-ATCF
10Sep . 06amGMT - - 12.7n59.6w - - 25knots - - 1009mb - - NHC-ATCF *12.6n59.6w
10Sep . 12pmGMT - - 12.9n60.0w - - 25knots - - 1009mb - - NHC-ATCF *12.8n60.2w
10Sep . 06pmGMT - - 13.2n60.5w - - 25knots - - 1009mb - - NHC-ATCF *13.2n60.4w
11Sep . 12amGMT - - 13.4n61.6w - - 25knots - - 1009mb - - NHC-ATCF *13.4n61.1w*13.5n61.8w
11Sep . 06amGMT - - 13.7n62.6w - - 25knots - - 1009mb - - NHC-ATCF *13.8n62.9w
11Sep . 12pmGMT - - 14.1n64.1w - - 25knots - - 1009mb - - NHC-ATCF *14.0n63.6w
*Before the NHC reevaluated&altered the ATCF numbers.
11Sep . 06pmGMT - - 14.6n65.7w - - 25knots - - 1009mb - - NHC-ATCF
12Sep . 12amGMT - - 15.2n67.5w - - 25knots - - 1008mb - - NHC-ATCF
12Sep . 06amGMT - - 15.5n69.4w - - 25knots - - 1008mb - - NHC-ATCF
12Sep . 12pmGMT - - 15.7n70.7w - - 25knots - - 1007mb - - NHC-ATCF
12Sep . 06pmGMT - - 15.8n72.1w - - 25knots - - 1007mb - - NHC-ATCF
13Sep . 12amGMT - - 15.9n73.3w - - 20knots - - 1007mb - - NHC-ATCF
13Sep . 06amGMT - - 16.1n74.7w - - 20knots - - 1007mb - - NHC-ATCF

Copy &paste 15.5n69.4w-15.7n70.7w, 15.7n70.7w-15.8n72.1w, 15.8n72.1w-15.9n73.3w, 15.9n73.3w-16.1n74.7w, pnd, trb, nbw, vqs into the GreatCircleMapper for a look at the last 24hours.
Member Since: Posts: Comments:
3746 TORMENTOSO83 "Igor is gonna strike PR!!!!"

Considering it's still 1100miles away from Vieques, exclamation points are more than slightly premature... especially when nothing points H.Igor towards a PuertoRico landfall.
Member Since: Posts: Comments:
Rain starting to come down in Kingston Jamaica now but not much wind yet, hope it stays this way :)
Member Since: Posts: Comments:
why arent the model out for igor on wu?
Member Since: Posts: Comments:
Igor is expanding in size this AM. It looks like a CAT 5, in terms of eye size and rotation at the center.
Member Since: Posts: Comments:
3748. JLPR2
Well I'm off to bed, night all!
Member Since: Posts: Comments:
Quoting RyanFSU:
Julia never makes it past 30N in the ECMWF 00Z run, but gets stuck due to the binary interaction with Igor. What a crazy situation the NHC has to deal with...


It'll definitely be interesting to see how much of this verifies over the next few days.
Member Since: Posts: Comments:
Igor is gonna strike PR!!!!
Member Since: Posts: Comments:

Viewing: 3796 - 3746

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Partly Cloudy
45 °F
Partly Cloudy

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron